I have replaced the Power steering pump, Rack and Pinion, Fluid, Cleaned the Solenoid Filter, and hoses.

The steering works flawlessly at speed.. but at a dead stop, at idle (600Rpms) it just doesn't. It is like it has zero power steering aid. Very hard to turn the wheels. If I put it in neutral and rev it slightly the steering comes back. There are zero leaks.

The power steering pump was just done today, as I thought that was the last thing it 'could' be. But no dice.

Have something to contribute?

You still have air in it, simple as that. These cars are very difficult to get all the air out. Best way is jack up the front. Sit next to a front wheel and move it full length to the left and then the right. Make sure the filler cap is off and don't let it run out of gluid. Repeat at least 50 times.

HiI'd agree with Bigste... I'd go for air in the system. There might be a bleed nipple somewhere on the system that you can connect a pipe to and bleed out the fluid until no bubbles are seen.

Glenn

Hey guys,

I have a 1994 LS 400.

I have replaced the Power steering pump, Rack and Pinion, Fluid, Cleaned the Solenoid Filter, and hoses.

The steering works flawlessly at speed.. but at a dead stop, at idle (600Rpms) it just doesn't. It is like it has zero power steering aid. Very hard to turn the wheels. If I put it in neutral and rev it slightly the steering comes back. There are zero leaks.

The power steering pump was just done today, as I thought that was the last thing it 'could' be. But no dice.

I hope , wish it is just 'air' -- That is hard for me to believe,.. Just air in the system is going to cause it to act like it has no power steering assist at idle/not moving ,.. but if I rev it up a little it works fine?

Really?

I'll jack it up and turn it a million times. How do I know I've gotten the air out?

Anyhow.. a mechanic put it on.. I get all kinds of replys.. at other lexus forums, people all say its a bad pump .. replace it again. I say BS,.. if it was a bad pump it wouldn't work at all. It is something else.

If it isn't air, it is either the Air control valve, or the Solenoid acting up.

But, air in the system will make this identical problem?

I would figure it would be randomly going in and out while driving down the road with air in the system.. (it doesn't). Bleh.. anyhow.. I'll jack it up and turn the wheel a bunch.

If any of you can explain how the Air control valve works on the LS 400 -- and also the Solenoid I'd be very grateful. I'd like to know how they engage, why they engage, and disengage, and what purpose they serve. So I know what to look for and what problems each device would cause if going bad.

Okay Neo get your drift. It is hard to believe that it might just be air. I find it harder to believe that a new pump is faulty. As for the ACV I think that dampens the steering at high revs. Most members agree that for what it does it can be dispensed with without any noticable effect. I've an idea on the solinoid but not too sure so I'll leave that for someone else. One thing for sure is that bleeding will cost you nowt and I am VERY confident it will cure it. Just one question. When you had new pump fitted was that with a new reservoir, usually the res is not included. If not you could be suffering from a blocked reservoir filter. This would cause the pump to malfunction until the pressure built up in the system (higher revs) thus forcing fluid through the blocked filter but lower revs would not give enough pressure to pass the blockage. Hope you get it sorted soon. If you want to remove the res you'll need a new O ring and I've posted plenty on here and other forums about the procedure. It's an easy job and a couple of hours is allowing time for a brew.

Okay Neo get your drift. It is hard to believe that it might just be air. I find it harder to believe that a new pump is faulty. As for the ACV I think that dampens the steering at high revs. Most members agree that for what it does it can be dispensed with without any noticable effect. I've an idea on the solinoid but not too sure so I'll leave that for someone else. One thing for sure is that bleeding will cost you nowt and I am VERY confident it will cure it. Just one question. When you had new pump fitted was that with a new reservoir, usually the res is not included. If not you could be suffering from a blocked reservoir filter. This would cause the pump to malfunction until the pressure built up in the system (higher revs) thus forcing fluid through the blocked filter but lower revs would not give enough pressure to pass the blockage. Hope you get it sorted soon. If you want to remove the res you'll need a new O ring and I've posted plenty on here and other forums about the procedure. It's an easy job and a couple of hours is allowing time for a brew.

Yes -- the reman'ed PS pump had a new reservoir -- Which I liked of course,.. so it wouldn't have the gunk from the old one.

So you think a flush will cure this? Hrmm.. I might go take off that solenoid and check the screen again -- I have plenty of ATF fluid for it. Thing is, on another forum everyone is saying it is 99% the new PS pump that is bad. I just don't know -- yeesh.

The mechanic is willing to to figure it out, so that is good.. But I'd like to figure it out on my own of course. I'll do what I can.. I guess pull the solenoid off and clean that screen again. It was clean last time. Most all of the fluid drains out when I do this anyhow -- But I have 6-7 quarts of fluid, so plenty to flush it with.. Maybe with the flush I can eliminate any air in the system.. then while it is jacked,.. do the lock to lock slowly about 50 times with cap off.

after all of that, isn't much more I can do. I"d like to plug the ACV, but I don't know exactly what to do here.. wish I had a picture/guide write up on how to do it. What part to buy, and what/how to loop things proper. I see the lines, just don't know what to do to plug. (The ACV might not even be bad, but it doesn't hurt things to plug it I know).

If you want to plug it here goes. The item you replace is difficult to get at, it's the bit that has 2 pipes running to it at the bottom of the pump. You replace it with at standard oil drain plug which is 14mm X 1.5 thread. Use PTFE tape on the plug. Having said that I think you should just doing the flush & bleed for now. I find it inconcievable that it's a bad pump. Trust me!

If you want to plug it here goes. The item you replace is difficult to get at, it's the bit that has 2 pipes running to it at the bottom of the pump. You replace it with at standard oil drain plug which is 14mm X 1.5 thread. Use PTFE tape on the plug. Having said that I think you should just doing the flush & bleed for now. I find it inconcievable that it's a bad pump. Trust me!

I'm just doing it all while I'm at it. Overhauling the system if you catch my drift.

It has a new pump and new rack.

So I jacked it up -- removed wheels.. Took off solenoid, removed screen.. cleaned it up (was already clean).. Tested the solenoid with 12volts.. it clicks.. so it works.

Put solenoid back on.

Then got to the ACV from the bottom -- Hardest part was removing the engine shield.

Was a pain to get to.. the HP hose it in the way and the sway bar.. but it isn't so bad.

I undid both the vacuum lines first. From both ends,.. and took them out of the car -- Won't be using them anymore.

I didn't have a 17mm box wrench so I had to go to the store.

Whlie I was there I got some caps for the intake,.. and a screw to plug the intake port on the left. (The right one has a metal port/nipple) -- The left one is plastic, and broken off a bit.. So I am using a screw of the right size with some waterpump sealent around it. --(This is a permenant thing for me).

Anyhow.. -- The soleniod leaked a good half quart at least of fluid.. I caught that.. and reservoir was empty.

So when I undid the ACV I thought it would be empty -- wrong! It started coming out .. ack. a little bit on alternator.. I did the best I could with it.. but made a bit of a mess.

Anyhow, I picked up a 14mm x 1.5 bolt like was recommended.

The thread pattern is slightly different than our ACV's. It fits, it is 14mm -- but at about 1/4 of the way in, it starts to strip the threads.. I could see metal shavings .. -- I backed it out and tried 15 different ways.. it wasn't going to go with some good force.. so I didn't want to mess the thread pattern up.

I took it to the store again, and they saw the difference (I had the ACV off to compare to) -- They said I would need to find a 14mm with the metric type thread pattern.. So basically I've got to find a bolt of the same size threaded slightly different.

Is about taking the ACV I pulled out, and just turning it into a plug. People have done this sucessfully, and it DOES fit,.. - So that makes the most sense. Take off the plastic backing, and filling the center of the bolt with something. If you have ideas or know how best to go about this, let me know. Otherwise I'm just going to do it tommorow, unless I can find the right bolt --(I think I might have a problem with that though).

I think some people take the 14Mx1.5 -- (It is an oil pan drain bolt) .. and force it in.. tearing up the ACV threads. It will go in, but removing it even once and it wouldn't go back in.. and if someone wanted to put the ACV back on.. no dice.. new pump needed. -- Also I just wouldn't trust the seal on it cross threading it all the way up with force.

I know this bolt I purchased is the same everyone else is getting.. it uses a 5/8ths wrench to tighten it.. is labeled 14Mx1.5" -- Says on the package it is an oil drain plug.. has a rubber gasket with it.

I've seen several people use rubber gaskets on their bolts.. Some use crusher washers -- and you say use teflon tape? (PTFE) ? --

I think they all work.

In fact, the ACV has no gasket on it.. It just screws in, and doesn't leak. So I think things will be sealed tight. Though with the heat and such, I will use a gasket at least.. I might put on some teflon, I probably will just to be double sure on the leak prospect.

--

The Vacuum lines I pulled off, one of them had a bit of PS fluid in it.. So that is a tale tale sign there was a leak from the ACV,.. right? Only air should be coming from those lines, right?

Removing ACV, and plugging it -- Removing vaccuum lines, and capping them on intake. (Done) -- Still need to plug.

Then once I get the ACV plugged tommorow.. (car is up on jackstands right now, wheels off.. tools by the vehicle ready to go) -- I am going to make sure its all sealed up.. Then remove the return lower hose. Attach my own hose to the return and have it flow into a bucket. Fill the reservoir about halfway -- 3/4ths maybe. Turn on the car. Immediately turn it off. Check the drain.. fill it back up -- Turn on, turn off.

Repeat until fluid is nice and clean. Then attached return back to pump.

Turn it back on at that point, and turn the wheels once. Get out, check levels.. (Cap off the whole time).

If it hasn't gone down, I am then going to turn on car, and move wheels lock to lock about 10 times and keep it running and check fluid. If at that time fluid still isn't moving.. I will proceed to move wheels slowly lock to lock at least 50 times.

Put on cap,.. move wheels a few more times.. Check for leaks before lowering.. and lower the car down.

** I don't honestly expect this to solve my problem, but it is something I needed to do any way, due to the ACV leaking slightly -- So why not.. The fluid has a little dark tint to it, so it needs a good flushing. With the solenoid being off, and the acv off.. need to bleed well.. (also PS pump replaced a few days ago) -- Lots of chances for air, which is why the flush should be good for ridding any air bubbles that might be trapped in the system.

main thing I need from you guys is the 'how to' on how to transform my ACV into a plug. Again, that makes the most sense because it is a perfect fit, it is a bolt, with a nut. Remove the backing ( plastic) .. and then fill the middle.

I was think of tapping the inside of the bolt, and putting a screwn in it.. (No head, flush mount).. leave a touch of room few microns. Then tacking the end flush with my MIG welder to ensure no movement by screw inside. -- Think that will do the job?

Also,.. the ACV came out with no gasket or teflon. So I think putting a rubber gasket on it, and wrapping threads in teflon should prevent any possible leaks . That is double precautionary.

If anything you read looks wrong, let me know, and if you have a better idea on the ACV turned into a plug , please let me know. If you've turned your ACV into a plug -- Please tell me how you did it.. (just to make things easier).

Lastly, if you know the exact terminology for the bolt I need for the plug , let me know. The thread pattern is slightly different, I assure you on the part I got, even though it is the right size. 14Mx1.5 (M for metric I'm sure).

14Mx1.5 is a metric bolt with a diameter of 14mm and a thread pitch (distance between threads) of 1.5mm. This is a pretty standard size, there are others with a pitch of 1mm 2mm etc. I would imagine yours is a 1mm thread if it goes on a few turns then tightens up.

Good luck with the fix, if this is a new pump why not get it replaced under warantee?